1TMPNAM(3P) POSIX Programmer's Manual TMPNAM(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 tmpnam — create a name for a temporary file
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16 #include <stdio.h>
17 char *tmpnam(char *s);
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21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
24 defers to the ISO C standard.
25 The tmpnam() function shall generate a string that is a valid pathname
27 that does not name an existing file. The function is potentially capa‐
28 ble of generating {TMP_MAX} different strings, but any or all of them
29 may already be in use by existing files and thus not be suitable return
30 values.
31 The tmpnam() function generates a different string each time it is
33 called from the same process, up to {TMP_MAX} times. If it is called
34 more than {TMP_MAX} times, the behavior is implementation-defined.
35 The implementation shall behave as if no function defined in this vol‐
37 ume of POSIX.1‐2008, except tempnam(), calls tmpnam().
38 The tmpnam() function need not be thread-safe if called with a NULL
40 parameter.
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43 Upon successful completion, tmpnam() shall return a pointer to a
44 string. If no suitable string can be generated, the tmpnam() function
45 shall return a null pointer.
46 If the argument s is a null pointer, tmpnam() shall leave its result in
48 an internal static object and return a pointer to that object. Subse‐
49 quent calls to tmpnam() may modify the same object. If the argument s
50 is not a null pointer, it is presumed to point to an array of at least
51 L_tmpnam chars; tmpnam() shall write its result in that array and shall
52 return the argument as its value.
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55 No errors are defined.
56 The following sections are informative.
58
60 Generating a Pathname
61 The following example generates a unique pathname and stores it in the
62 array pointed to by ptr.
63 #include <stdio.h>
65 ...
66 char pathname[L_tmpnam+1];
67 char *ptr;
68 ptr = tmpnam(pathname);
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72 This function only creates pathnames. It is the application's responsi‐
73 bility to create and remove the files.
74 Between the time a pathname is created and the file is opened, it is
76 possible for some other process to create a file with the same name.
77 Applications may find tmpfile() more useful.
78 Applications should use the tmpfile(), mkstemp(), or mkdtemp() func‐
80 tions instead of the obsolescent tmpnam() function.
81
83 None.
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86 The tmpnam() function may be removed in a future version.
87
89 fopen(), open(), mkdtemp(), tempnam(), tmpfile(), unlink()
90 The Base Definitions volume of POSIX.1‐2008, <stdio.h>
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94 Portions of this text are reprinted and reproduced in electronic form
95 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
96 -- Portable Operating System Interface (POSIX), The Open Group Base
97 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
98 cal and Electronics Engineers, Inc and The Open Group. (This is
99 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
100 event of any discrepancy between this version and the original IEEE and
101 The Open Group Standard, the original IEEE and The Open Group Standard
102 is the referee document. The original Standard can be obtained online
103 at http://www.unix.org/online.html .
104 Any typographical or formatting errors that appear in this page are
106 most likely to have been introduced during the conversion of the source
107 files to man page format. To report such errors, see https://www.ker‐
108 nel.org/doc/man-pages/reporting_bugs.html .
109IEEE/The Open Group 2013 TMPNAM(3P)